The present invention relates to an apparatus and method of monitoring and controlling a power system having an alternating current bus.
Devices that monitor and/or control various electrical parameters, such as voltage, current, and power utilized by one or more loads connected to an alternating current bus of a power system are known. These devices can be used to determine such things as inefficient uses of electricity and detect problems on the alternating current bus. Such devices may also be used to manage loads connected to the bus by controlling these parameters. Such control can help reduce or eliminate inefficiencies and prevent damage to the alternating current bus. Such control can also help actuate the one or more loads as desired.
The present invention is an improvement over these devices. An embodiment of the present invention includes a monitoring and control apparatus for a power system having an alternating current bus which includes at least one line, a neutral, and a ground. The apparatus includes a module coupled to the bus for digitizing either or both a voltage waveform or a current waveform, both of which may appear on the bus. The voltage and current waveforms may be sinusoidal, with a frequency of approximately 60 Hz. The module may also modulate the digitized waveform onto a carrier. The apparatus also includes a control unit that is coupled to the bus which demodulates the digitized waveform and calculates at least one of the following: average current, root mean square current, peak current, current crest factor, average voltage, root mean square voltage, peak voltage, voltage crest factor, voltage surge, current waveform shape, voltage waveform shape, current waveform harmonic structure, and voltage waveform harmonic structure.
The apparatus may further include a second module coupled to the bus that is responsive to a predetermined condition at the first module. The first module may be programmed by the control unit to sense a condition at that module and direct the second module to respond as a result of that condition. The control unit may be configured to control at least one of the following: the power supplied to a load at one or more of the modules, activation/deactivation of one or more of the modules, digitization of the voltage waveform, the current waveform, or both the voltage and current waveforms on the bus at one or more of the modules, and transmission of the digitized waveform to the control unit. The modules may each include a transceiver and the control unit may also include a transceiver, each of which are configured to transmit and receive radio frequency signals. A load may be coupled to each module and the module configurable to control a load voltage, a load current, or both the load voltage and the load current.
The module may rectify the voltage waveform, the current waveform, or both the voltage and current waveforms before digitizing the waveform. This rectification may be of full cycle of the waveform.
In one or more embodiments of the apparatus, the control unit may be a computer. Additionally, in one or more embodiments of the apparatus, the module and control unit may each include transceivers, that are configured to transmit and receive radio frequency signals. Furthermore, the module may be coupled to a load and configurable to control a load voltage, a load current, or both the load voltage and the load current.
An embodiment of apparatus constructed in accordance with the present invention may further include a second module coupled to a second alternating current bus which includes at least one line, a neutral, and a ground. The second module digitizes a second voltage waveform, a second current waveform, or both the second voltage waveform and the second current waveform on the second bus. Subsequent to digitizing, the second module modulates the digitized waveform onto a second carrier. This embodiment may include a second control unit that demodulates the digitized waveform of the second module and calculates at least one of the values that may be calculated by the first control unit. In this embodiment, the control units may be in communication with one another whereby one or more waveforms digitized by the second module are received by either control unit. At least one of the control units may be configured to control at least one of the following: the power supplied to a load at each of the modules, activation/deactivation of the modules, digitization of at least one of the first voltage waveform and the first current waveform by the first module, digitization of at least one of the second voltage waveform and the second current waveform by the second module, and transmission of the digitized waveforms to the control unit.
The present invention also is directed to a method of monitoring and controlling a power system having an alternating current bus which includes at least one line, a neutral, and a ground. The method includes the steps of rectifying a voltage waveform, a current waveform, or both the voltage and current waveforms which may appear on the bus. The method also includes the steps of digitizing the rectified waveform and transmitting the digitized waveform to a control unit. The method additionally includes the step of calculating at least one of the following: average current, root mean square current, peak current, current crest factor, average voltage, root mean square voltage, peak voltage, voltage crest factor, voltage surge, current waveform shape, voltage waveform shape, current waveform harmonic structure, and voltage waveform harmonic structure.
The method may also include the steps of programming a first module coupled to the bus to sense a predetermined condition at the first module and controlling a second module coupled to the bus in response to the predetermined condition at the first module. The method may additionally include the step of activating a module coupled to the bus to control at least one of the following: the power supplied to a load at one or more modules coupled to the bus, activation/deactivation of one or more of the modules, digitization of the voltage waveforms, the current waveforms, or both waveforms, and transmission to the control unit.
The method may further include the step of displaying the calculation. Also, the transmitting step may include the steps of modulating the digitized waveform onto a carrier and demodulating the digitized waveform at the control unit.
The method may additionally include the steps of programming a module coupled to the bus to sense a predetermined condition at the first module and controlling the module in response to the predetermined condition. Furthermore, the method may include the step of programming each module coupled to the bus to have an identifier that allows each module and the control unit to recognize each module coupled to the bus.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.